Which of the following statements is/are correct?
1. In June 2016, the LIGO group of scientists announced the detection of a second set of gravitational waves.
2. Gravitational waves were generated due to merger of two black holes at about 1.4 billion light-years distant.
3. Gravitational waves were inserted due to collision of two white dwarf stars at about 1.4 billion light-years distant.
Select the correct answer using the code given below.

Options

A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2 and 3